Longitudinal study of Toba/Qom communities reveals delay and shortening of sleep in real time.

Both rural and semi-urban Toba/Qom groups showed delays of close to 1 hour in sleep timing between 2012 and 2024.

• Longitudinal study from 2012 to 2024 of native Toba/Qom communities in northern Argentina.
• The dataset comprised over 12,000 actigraphically recorded sleep events from 156 participants.
• Analyses used linear mixed-effects models.
• The sample included rural groups newly introduced to electricity and semi-urban groups with earlier access to electricity.

Participants from rural communities lost about 35 minutes of sleep within the course of a decade.

• Sleep duration reduction was reported specifically for rural participants.
• Data were actigraphic recordings collected longitudinally at different times.
• The abstract describes the shifts as occurring in real time over about a decade.

The study period spanned electrification of rural communities after 2016 and later spread of internet and smartphone use.

• Rural communities were newly introduced to electricity after 2016.
• In more recent years, internet and smartphone use spread among the Toba/Qom.
• Semi-urban groups had earlier access to electricity, providing a comparison.

Electricity and internet/smartphone use cannot by themselves fully explain the observed shifts in sleep timing over time.

• Previous work in these and other populations has associated both factors with changes in sleep habits.
• The authors' analyses suggest these factors alone do not account for the timing shifts.
• The authors suggest the shifts may be consistent with concurrent broader processes of modernization and acculturation.

The findings provide direct longitudinal evidence for sleep delay and curtailment during early adoption of modern technologies, a contemporary parallel to hypothesized historical shifts in sleep with industrialization.

• The authors note direct longitudinal evidence of such changes is remarkably scarce.
• Changes occurred rapidly in communities going through early stages of adopting modern technologies.